In the field of the display technology, the flat panel display device, as the mainstream of the display device, is extensively applied in various kinds of customer electronic products such as mobile phones, TV sets, personal digital assistants, digital cameras, laptops, desktop computer due to its advantages such as high image quality, low power consumption, thinness, wide application range, etc. Currently, the thin film transistor (TFT) is the major driving element in a liquid crystal display (LCD) and an active matrix organic light-emitting diode (AMOLED), which directly relates to the improvement of high-performance flat panel display devices.
The thin film transistor has various kinds of structures, and many different kinds of materials may be used to form the active layer of the thin film transistor of respective structure. Metal oxide TFT is considered as the most promising substrate technology for the improvement of the display device in larger size and higher flexibility due to their characteristics such as high field-effect mobility (≥10 cm2/V·s), fast response and high transmittance in visual spectrum, etc. The metal oxide thin film transistor with a top-gate-self-aligned structure has no overlap between its source/drain electrode and its gate electrode, and thus possesses lower parasitic capacitance and better malleability, resulting in a reduction of signal delay during transmission. Additionally, the self-aligned manufacturing method may facilitate the fabrication of short channel devices and thus improve the device performance.
It is noted that, the information disclosed in this background section is merely used for the convenience of the reader to understand the background of the present disclosure, and may involve technical information in the prior art that is not well known yet to the person skilled in the art.